Substance use disorders among criminal offenders present a unique challenge to criminal justice and public health systems. These systems must balance punishment and rehabilitation while simultaneously dealing with addiction - a chronic, cyclical, and multidimensional disease that is pervasive among criminal offenders and requires long-term monitoring and extended care protocols (McLellan et al., 2000; Scott et al., 2003). Women offenders, approximately 70% of whom have substance dependence or abuse issues (BJS, 2002), are of particular concern from economic, clinical, and criminal justice perspectives as they represent the fastest growing subgroup in local jails (BJS, 2003). Women offenders are also more likely to have co-occurring mental health problems that further complicate their rehabilitation and recovery process upon reentering society (CASA, 2010). Moreover, the social and economic implications of addiction and criminality extend to the children of women offenders. The need to address substance use within the women offender population has generated interest in Recovery Management Checkups (RMCs), an evidence-based approach to promoting long-term recovery that provides clients with periodic monitoring, feedback, and linkage with treatment as needed. The Recovery Management Checkups for Women Offenders (RMC-WO) intervention is currently testing the long-term effectiveness of the RMC model with a group of women offenders coming out of jail. These interventions are designed to reduce substance use, HIV-risk behaviors, and criminal recidivism. Very little economic research has been conducted on community re-entry and long term monitoring models for women offenders that have the potential to improve long-term outcomes and lower total costs to society. In response to the pressing need for economic evaluations of RMCs, the proposed research project will estimate the costs, cost effectiveness, and net benefits of RMC-WO relative to a control condition. The specific aims of this research are as follows: 1. Estimate the economic cost (total and per client) of the RMC-WO intervention. 2. Estimate the cost effectiveness of RMC-WO relative to the control group over the three-year follow-up period for core outcomes (substance use, HIV risk behaviors, illegal activity) and ancillary outcomes (treatment engagement and treatment retention). 3. Obtain or derive appropriate monetary conversion factors and estimate the economic benefits of RMC- WO relative to the control group over the three-year follow-up period to form benefit-cost ratios and net benefit estimates. Successfully fulfilling these aims will not only advance scientific knowledge of the overall impact of addiction interventions for women offenders but also improve clinical practice by increasing our understanding of the financial considerations of implementing RMC-WO on a broader scale.